A toner for use in electrophotography (also known as photocopying) is configured with a binder resin, a coloring material, and a wax, or the like. However, in order to fix the toner onto the paper with low power or energy, it is desired that the glass transition point, also commonly called the glass transition temperature, of the toner is low. Generally, the lower the glass transition point is, the worse the storage preservation quality of the toner, and unification, i.e., fusing, of the toner particles or material occurs during transportation, or in the toner cartridge in transit or during residence in a copying machine main body prior to being used. In order to simultaneously support the fixability of the toner at a low glass transition point, and the storage preservation quality of that low glass transition point toner, crystalline polyester materials have recently been employed as a replacement for, or in addition to, wax in the toner.
However, there is a problem in that when crystalline polyester is used, the low temperature fixability of the toner improves, but the toner glass transition temperature Tg considerably decreases, and thus the preservative quality of the toner is considerably degenerated.